Will do.

Here's a thought....I have a trickle charger so as I'm not using the car at the moment, I could charge it overnight or so and see what the voltage is after taking the charger off for a while. Would this show that the current battery is at least capable of being charged and holding a higher charge, so isn't faulty?

Edited 8 August, 20169 yr by myjalopy

Will do.

Here's a thought....I have a trickle charger so as I'm not using the car at the moment, I could charge it overnight or so and see what the voltage is after taking the charger off for a while. Would this show that the current battery is at least capable of being charged and holding a higher charge, so isn't faulty?

Great plan, I didn't think to ask if you had such a charger.  Don't measure the voltage immediately after charging though, that gives a misleading impression, leave it a couple of hours.

myjalopy

Me and Wino have different opinions. I think the battery is faulty, Wino thinks it is the voltage regulator that is faulty. Nothing wrong with having a debate based on technical arguments. I have always advocated for such debates. Nobody knows all. We both have valid points and I respect his opinions. The problem is we didn't have enough proof (so far) to decide which is which. Not to mention we could both be right, meaning the battery is old AND the voltage regulator is dead. Having a headache, myjalopy? Wait, there is more. We could be both wrong Yes, we didn't take into account that a diode or more inside the alternator is/are bad, mostly based on diodes' reliability.

 

I must  mention though that I haven't seen so far a bad voltage regulator still capable of regulating 13.6V. They usually die completely and the battery light stays on all the time.

 

Charging the battery at home and measuring the next day the voltage on battery with the engine running is a better idea but still not enough to decide which is which. The only valid test is to measure suspect parts separately.

Edited 8 August, 20169 yr by RicardoM

I think the alternator as a whole has something wrong with it. The battery may also be past its best, but if it isn't given a chance we'll never know if it was recoverable.

I agree that the next most easy step is to charge the battery at home and run a new test on the car. But we will not know what failed first. Is it a bad VR that kept the battery undercharged? Or is it a bad battery that can't keep the charge thus having a too low voltage for VR to do its job properly?

 

Just in case anyone wants to know how to check parts separately, here is how I would do it or what I would ask to do in a garage:

 

The battery life can be tested using a battery load tester.

 

The voltage regulator can be tested by itself using an adjustable power supply, a 21W bulb and some wires.

 

The alternator can be tested for bad diode(s) by using an oscilloscope hooked on battery while the engine is running and watching the voltage ripple. Of course, ideally is to open the alternator and  measure all diodes with a multimeter.

myjalopy

You can live with a 45Ah battery if you want but I find it minimal. A battery acts as a "buffer" of electrical energy when you run multiple loads at once. You want a bigger buffer for additional devices too.

 

Yet "bigger is better" is not true. A bigger battery needs a bigger charging current. That puts a bigger strain on alternator and in turn on engine (bigger mechanical load, higher consumption).

 

I find the "sweet spot" or "best of both worlds" at 56 Ah for 1.3 engines on petrol.

Hi Chaps

 

Quite a debate on this but here's another bit of information that I did mention earlier that may help/hinder. The current alternator is a second hand one, the original one was replaced when the battery light kept coming on at lower and lower rpms until the car refused to start one day. I could coax it along with a charger until I managed to get another alternator. Once fitted, all has been well for the last five years. The noticed that the new alternator has a noticeable whistle at 3000rpm, which wasn't on the old one.

 

I''ll let you both know how the battery is tomorrow after a charge and a quick run down to Tesco.

 

If I get a new battery it will most likely be like for like as is fitted (44Ah), because my car has very little to drain it....no A/C, no EW etc.

Edited 8 August, 20169 yr by myjalopy

If I get a new battery it will most likely be like for like as is fitted (44Ah), because my car has very little to drain it....no A/C, no EW etc.

Just for informative purpose, Felicia 1.3i is equipped with a 70A alternator. Only models with A/C or PS are fitted with a 90A one.

 

The whistle coming from the alternator is mechanical in nature. The bearings or the pulley/belt do that usually.

 

Changing the old alternator as a whole without trying first a new voltage regulator doesn't help knowing what really failed.

My Felicia has PS, not sure what the alternator amperage is. The reason for changing the alternator rather than the VR before was because I couldn't find a VR for less than £30. The alternator cost me that and fixed the issue until now.

 

I've taken the charger off now and will check the batttery in a while. Then again aftter a quick run.

Edited 9 August, 20169 yr by myjalopy

Just for reference, I'm willing (and hopefully able) to act as a pair of robotic hands for Ricardo, if there turns out to be a potentially repairable fault with the alternator. I have a pair of bearings 'on stock' in my shed somewhere that are quite likely to be the right sizes, and various secondhand alternators that could possibly yield useful spare diodes etc.  I would almost certainly require guidance from Ricardo though, if he would be so kind.  

 

Don't suppose you kept the old alternator, myjalopy?

 I would almost certainly require guidance from Ricardo though, if he would be so kind. 

No problem. I've prepared (almost) step by step photos for every scenario. I am sure you will do a great job.

Hi Wino, thanks for the offer of help and I did keep the alternator for many years having only thrown it out last year.  

 

Just so you know, the battery was showing 12.3v earlier, but after a drive I went to test it again only to have the voltmeter pack up on me but still no battery light on yet.

 

I'll use your handy diagrams Ricardo, but need to get another meter first.

Hi chaps. I've been away since last posting and upon my return the Felicia started on the button and no warning lights. I will get around to checking it as suggested now that I'm back, so will report then.

regards

Just to let you know that after checking with my new tester and with no sign of the battery light since re-seating the VR, the voltage at the battery is 12.6v after leaving the car overnight.

Once started, the battery shows 14v across the terminals and testing the VR +ve terminal shows 14.08v.

 

For the past couple of weeks, I've driven to work with the headlights on and the blowers on to clear the screen, but all seems fine. There's still an underlying issue I presume, but i'll see how it goes for now.

Cheers.

Good news. That all sounds pretty healthy to me. 

Recently the batt light started to stay on as before, so taking the easy option I fitted a new voltage regulator as the carbon brushes were quite worn on one side and it's instantly cured. Been fine since. Thanks all.